To elaborate on why we need it, every computer graphic card speaks a different language. A set of cards from the same manufacturer might speak almost the same language, but it will not be exact, like two people speaking Chinese except with different dialects. In the early days of computer gaming, you would need to ensure that your graphic card was actually listed as a supported card. You would have to go through a small list of cards and try and find your exact model number. And if the developers decided they did not want to deliberately add the support, too bad. Computers can be incredibly difficult to work with, even with the slightest inconsistency. A full stop in the wrong place could crash your entire system.